:root {
  --background: #f6f7f9;
  --panel: #ffffff;
  --text: #15171a;
  --muted: #667085;
  --border: #d8dde5;
  --accent: #007aff;
  --accent-hover: #0066d6;
  --danger: #b42318;
  --shadow: 0 18px 60px rgba(19, 27, 43, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--background);
  color: var(--text);
  font-family:
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
}

body {
  min-height: 100%;
  margin: 0;
}

button,
input {
  font: inherit;
}

.shell {
  display: flex;
  width: 100%;
  min-height: 100vh;
  align-items: flex-start;
  justify-content: center;
  padding: 40px 18px;
}

.panel {
  width: min(100%, 760px);
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 28px;
}

.header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
  line-height: 18px;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: 32px;
  font-weight: 700;
  line-height: 1.15;
}

.docs-link {
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  line-height: 24px;
  text-decoration: none;
}

.docs-link:hover {
  text-decoration: underline;
}

.intro {
  max-width: 620px;
  margin: 16px 0 26px;
  color: var(--muted);
  font-size: 16px;
  line-height: 24px;
}

.validator-form {
  display: grid;
  gap: 8px;
}

.validator-form label {
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  line-height: 20px;
}

.input-row {
  display: flex;
  gap: 10px;
}

.input-row input {
  width: 100%;
  min-width: 0;
  height: 44px;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 16px;
  padding: 0 12px;
}

.input-row input:focus {
  border-color: var(--accent);
  outline: 3px solid rgba(0, 122, 255, 0.18);
}

.input-row button {
  height: 44px;
  border: 0;
  border-radius: 6px;
  background: var(--accent);
  color: #ffffff;
  cursor: pointer;
  font-size: 15px;
  font-weight: 700;
  padding: 0 18px;
}

.input-row button:hover {
  background: var(--accent-hover);
}

.input-row button:disabled {
  cursor: not-allowed;
  opacity: 0.62;
}

.status {
  min-height: 24px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 14px;
  line-height: 24px;
}

.status.error {
  color: var(--danger);
}

.results {
  margin-top: 12px;
}

.results:empty {
  display: none;
}

.results h2 {
  font-size: 22px;
}

.results textarea,
.results pre {
  max-width: 100%;
  border: 1px solid var(--border);
  border-radius: 6px;
}

@media (max-width: 560px) {
  .shell {
    padding: 18px 12px;
  }

  .panel {
    padding: 20px;
  }

  .header {
    align-items: flex-start;
    flex-direction: column;
  }

  h1 {
    font-size: 28px;
  }

  .input-row {
    flex-direction: column;
  }
}